Spatial, temporal and source contribution assessments of black carbon over the northern interior of South Africa

Chiloane, K.; Beukes, J. P.; Zyl, P. G. van; Maritz, Petra; Vakkari, Ville; Josipovic, Miroslav; Venter, Andrew D.; Jaars, Kerneels; Tiitta, Petri; Kulmala, Markku; Wiedensohler, Alfred; Liousse, Catherine; Mkhatshwa, Gabi; Ramandh, Avishkar; Laakso, Lauri

doi:10.5194/acp-17-6177-2017

Cited by 34 publications

(33 citation statements)

References 63 publications

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“…The atmospheric lifetime of BC varies from a few days to weeks; therefore, BC undergoes both regional and intercontinental transport (Bond et al, 2013). During transport, its mixing state, morphology and optical properties change (China et al, 2015). As a result, BC has been observed in remote areas such as the polar regions (Huang et al, 2010;Weller et al, 2013;Qi et al, 2017;Xu et al, 2017) and the Tibetan Plateau (Cong et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

Zheng

Kong

et al. 2019

Atmos. Chem. Phys.

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Abstract. Black carbon (BC), which is formed from the incomplete combustion of fuel sources (mainly fossil fuel, biofuel and open biomass burning), is a chemically inert optical absorber in the atmosphere. It has significant impacts on global climate, regional air quality and human health. During transportation, its physical and chemical characteristics as well as its sources change dramatically. To investigate the properties of BC (i.e., mass concentration, sources and optical properties) during intra-regional transport between the southern edge of the North China Plain (SE-NCP) and central China (CC), simultaneous BC observations were conducted in a megacity (Wuhan – WH) in CC, in three borderline cities (Xiangyang – XY, Suixian – SX and Hong'an – HA; from west to east) between the SE-NCP and CC, and in a city (Luohe – LH) in the SE-NCP during typical winter haze episodes. Using an Aethalometer, the highest equivalent BC (eBC) mass concentrations and the highest aerosol absorption coefficients (σabs) were found in LH in the SE-NCP, followed by the borderline cities (XY, SX and HA) and WH. The levels, sources, optical properties (i.e., σabs and absorption Ångström exponent, AAE) and geographic origins of eBC were different between clean and polluted periods. Compared with clean days, higher eBC levels (26.4 %–163 % higher) and σabs (18.2 %–236 % higher) were found during pollution episodes due to the increased combustion of fossil fuels (increased by 51.1 %–277 %), which was supported by the decreased AAE values (decreased by 7.40 %–12.7 %). The conditional bivariate probability function (CBPF) and concentration-weighted trajectory (CWT) results showed that the geographic origins of biomass burning (BCbb) and fossil fuel (BCff) combustion-derived BC were different. Air parcels from the south dominated for border sites during clean days, with contributions of 46.0 %–58.2 %, whereas trajectories from the northeast showed higher contributions (37.5 %–51.2 %) during pollution episodes. At the SE-NCP site (LH), transboundary influences from the south (CC) exhibited a more frequent impact (with air parcels from this direction comprising 47.8 % of all parcels) on the ambient eBC levels during pollution episodes. At WH, eBC was mainly from the northeast transport route throughout the observation period. Two transportation cases showed that the mass concentrations of eBC, BCff and σabs all increased, from upwind to downwind, whereas AAE decreased. This study highlights that intra-regional prevention and control for dominant sources at each specific site should be considered in order to improve the regional air quality.

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Section: Introductionmentioning

confidence: 99%

Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

Zheng

Kong

et al. 2019

Atmos. Chem. Phys.

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“…The regional impacts of household combustion from towns and cities within a 50 to 100 km radius will influence the air masses measured at Welgegund. A recent study indicated the regional impact of household combustion on black carbon in the north-eastern interior of South Africa [47], while the influence of household combustion on PM10 measured in the industrialised Western Bushveld Igneous Complex that is also one of the major source regions impacting Welgegund was also revealed [48]. The ƩNRRFs of two specific nitrile compounds, i.e.,2,4-pentanedinitrile and cyanogen, which were also detected in other samples that were collected throughout the sampling period, were significantly higher in the PM1 size fraction in the sample collected on 10 May 2011.…”

Section: Nitriles Amides and Ureamentioning

confidence: 99%

Characterising Particulate Organic Nitrogen at A Savannah-Grassland Region in South Africa

et al. 2019

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Although atmospheric organic N compounds are considered to be important, especially in new particle formation and their contribution to brown carbon, these species are not that well understood. This can be partially attributed to their chemical complexity. Therefore, the aim of this study was to assess the characteristics of organic N compounds utilising comprehensive two-dimensional gas chromatography coupled with a time-of-flight mass spectrometer (GCxGC-TOFMS) in aerosol samples that were collected at a savanna-grassland background region and to determine the possible sources. 135 atmospheric organic N compounds were tentatively characterised and semi-quantified, which included amines, nitriles, amides, urea, pyridine derivatives, amino acids, nitro-and nitroso compounds, imines, cyanates and isocyanates, and azo compounds. Amines contributed to 51% of the semi-quantified concentrations, while nitriles, pyridine derivatives, and amides comprised 20%, 11%, and 8%, respectively, of the semi-quantified concentrations. Amines, nitriles, amides, and pyridine derivatives concentrations were higher during the dry season, which were attributed to meteorology and open biomass burning. Anthropogenic sources impacting air masses measured at Welgegund, as well as regional agricultural activities, were considered as the major sources of amines, while the regional influence of household combustion was most likely the main source of nitriles, amides, and pyridine derivatives. The other organic N species were most likely related to the influence of local and regional agricultural activities.

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“…In contrast, it was higher than measured values in Santa Cruz de Tenerife (Spain), Crete (Greece) and Finland. Chiloane et al, (2017) recorded BC mean concentrations ranging between 0.7 and 1.4 µgm -3 in background sites and sites influenced by industrial activities and/or nearby settlements in South Africa.…”

Section: Black Carbon Variabilitymentioning

confidence: 99%

Measurement of atmospheric black carbon in some South Mediterranean cities

Merabet

Kerbachi²,

Mihalopoulos³

et al. 2019

Clean Air J.

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This study aims to investigate, for the first time in Algeria, the atmospheric black carbon (BC) concentrations over one year measured at the Scientific Observatory of Algiers and to compare their concentration levels with other Mediterranean cities (i.e., Athens and Crete). The diurnal cycles as well as seasonal variations of BC concentrations were evaluated and attributed to their emission sources (fossil fuel: BCff and wood burning: BCwb). The annual mean concentrations of BC, BCff and BCwb were 1.113±2.030, 1.064±2.002 and 0.049±0.262 µgm-3, respectively. The highest seasonal mean concentrations were recorded in summer and autumn with 1.283±1.346 and 1.209±1.149 µgm-3 for BC and 1.217±1.431 and 1.177±1.151 µgm-3 for BCff, respectively. However, the lowest mean concentrations were recorded in winter and spring with 1.023±1.189 and 0.966±0.964 µgm-3 for BC and 0.933±1.177 and 0.956±0.874 µgm-3 for BCff, respectively. For BCwb, the highest mean concentrations were reached in winter and summer with 0.090±0.055 and 0.066±0.050 µgm-3, respectively, very likely due to the forest fires and long-range transport of air pollution from Europe. The lowest mean concentrations of BCwb were recorded in autumn and spring with 0.032±0.033 and 0.010±0.021 µgm-3, respectively. Seggregating BC levels into eight wind sectors, showed that the prevailing BC pollution with concentrations reaching up to 5.000 µgm-3 originated from the North-West wind sector. A source apportionment of BC for the wet and dry period was also perfomed followed by a back trajectory cluster analysis for long-range transport.

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Spatial, temporal and source contribution assessments of black carbon over the northern interior of South Africa

Cited by 34 publications

References 63 publications

Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

Intra-regional transport of black carbon between the south edge of the North China Plain and central China during winter haze episodes

Characterising Particulate Organic Nitrogen at A Savannah-Grassland Region in South Africa

Measurement of atmospheric black carbon in some South Mediterranean cities

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